Range Report Bbl length, bullet weight, & velocity

[dbooksta]

In general a shorter barrel is capable of producing lower velocities from a given cartridge, holding bullet weight constant.

Also, a heavier bullet is slower than a lighter bullet in the same cartridge.

<span style="font-weight: bold">Does any general relationship hold between all three factors?</span> E.g., are either of the following statements true?

A. A heavier bullet loses less velocity (in percentage terms) in a shorter barrel than a lighter bullet in the same cartridge?

B. A heavier bullet loses more velocity (in percentage terms) in a shorter barrel than a lighter bullet in the same cartridge?

For example: I am used to shooting 5.56mm from 16" barrels. Now I'm getting a 11" barrel. If I work up optimal loads for each, can I expect my 11" muzzle velocity to be closer to the 16" (in percentage terms) with 50gr bullets or with 70gr bullets?

Another example: I am working up .44mag loads in a 3" snubby. The load manuals typically list velocities from 8-10" barrels. Should I expect my peak velocities be closer to the manuals' (in percentage terms) with a 180gr bullet or with a 300gr?

 

[hue001t]

Re: Bbl length, bullet weight, & velocity

tag id be interested to know as well.

 

[BryanLitz]

Re: Bbl length, bullet weight, & velocity

I think it depends a lot on the powder.

Using a faster burning powder in the short barrel seems like a good way to maintain velocity as high as possible for any bullet.

Even with faster powder, I would expect the heavy bullet to suffer more velocity loss in a shorter barrel than a lighter bullet. This is just a hunch though.

-Bryan

 

[bdh308]

Re: Bbl length, bullet weight, & velocity

Keep in mind also your twist rate on your barrel. That plays a significant part velocity and stabalization. I am no guru like Bryan but from what I understand the shorter the barrel the faster the twist to maintain these factors. Bryan by the way I love your work. Thank you for all your research you have done over the years. If it wasnt for you I wouldnt understand a fraction of what really goes on as far as ballistics go.